Traditionally, nucleic acids have been precipitated by the addition of various salts and ethanol or isopropanol (Eickbush and Moudrianakis, 1978). Methods for binding nucleic acid to a solid substrate are also well known in the art. However, these methods have traditionally required the addition of salts or other compounds or the manipulation of pH that could adversely effect the downstream application of the isolated molecules or require additional purification steps.
Reversible DNA binding to carboxylated beads is described in U.S. Pat. Nos. 5,898,071 and 6,310,199. These patents detail methods for DNA purification using carboxylated encapsulated magnetic particles. However, the disclosed methods require precise adjustments of salt and polyethylene glycol concentrations ('071 patent) or pH ('199 patent). As is well known in the art, high salt and PEG contamination may adversely effect downstream applications of the isolated nucleic acid, mandating an additional purification step. Further, modifying the pH of a solution can adversely affect DNA structure. The instant invention overcomes the noted deficiencies in the art by providing methods and compositions for the rapid and efficient purification of nucleic acids in which contaminants such as salts and/or PEG are not present and in which pH is not significantly altered.